A student uses a pencil to write in class at Pengying School on the outskirts of Beijing November 11, 2013. REUTERS/Jason Lee BEIJING (Reuters) - A Chinese official has suggested the biting of pencils as a possible explanation for excessive levels of lead found in children in a town in the south of the country located next to a chemical plant, state media reported on Monday.

The plant, in Dapu in the southern province of Hunan, has been shut down after tests found that more than 300 children had excessive levels of lead in their blood, the Global Times, published by the ruling Communist Party's official People's Daily, said.

Su Genlin, head of the Dapu government, said the children could have been made sick by "biting pencils", the newspaper reported, despite the fact that the "lead" in pencils is graphite.

The government has now announced a probe into both the owner of the chemical plant and local environmental protection agency, the report added.

Chinese media frequently report on similar cases in a country where breakneck economic growth has come at a terrible price for the natural environment in many places.

In 2009, a smelter was closed after it was blamed for the lead poisoning of almost 1,000 children in the northern province of Shaanxi.

Despite repeated pledges to get tough, the government faces an uphill struggle in poorer parts of the country where local authorities often rely on tax receipts from heavily polluting industry.